TRVs and Room Thermostats

[AndrewSchofield]

I have a little knowledge of plumbing and central heating systems but i am by no means a plumber. I've recently replaced the old rad valves in our house with TRVs and was told that i should retain the room thermostat but set it to max and then set the TRVs to the required temp. I have done this but on thinking about this further i understand that the TRVs only shut off the radiators they are attached to and will not turn the boiler off (we have a combi boiler)? Or does the boiler recognise that all the rads are shut off and turn itself off?

Should i turn the Room thermostat (which is in the hall) down to a more reasonable temp so it turns the boiler off at some point rather than running constantly and should the TRV on rad in the hall (with the Room Thermostat) be set to maximum?

 

[Richard C]

TRV’s should not be fitted to ALL the radiators on the system; unless it has a bypass loop you could end up damaging the boiler. The radiator in the room where the thermostat is located should not have TRV fitted; control individual room temperatures by properly balancing the system & adjusting each TRV to give the desired room temperature. The system should then regulate itself via the room thermostat, shutting the boiler down when it is up to temperature.

 

[D_Hailsham]

I ... was told that i should retain the room thermostat but set it to max and then set the TRVs to the required temp. ... Or does the boiler recognise that all the rads are shut off and turn itself off?

There are some boilers which will turn themselves off without the need for a room thermostat. But, speaking generally, whoever told you to leave the stat on Max was talking b**ll*x.

Should i turn the Room thermostat (which is in the hall) down to a more reasonable temp

Yes

should the TRV on rad in the hall (with the Room Thermostat) be set to maximum?

Ideally there should not be a TRV on the rad controlled by the wall stat. If You don't want to change it back to a wheel valve, setting it to max is OK.

If you find that the wall stat turns the boiler off before other rooms get up to temperature and their TRVs operate, you need to reduce the heat output of the radiator in the hall. If you still have the TRV, you will need to closed down the lockshield valve a bit at a time until its OK. Otherwise close down the wheel valve.

 

[AndrewSchofield]

Thanks guys - was basing my theories on my logical thinking rather than any definate knolwedge but it appears i was right to check it out on this forum!! For interest its a Worcester Bosch 28CDi combi but i've no idea whether it shuts down when the rads are turned off or not? To be honest i haven't noticed the boiler running constantly when the heating is on but not sure what is making it shut down!

Will get on the blower to the missus and tell her to turn the room stat down asap!!! Will set the TRV in the hall to max and maybe think about puttting the old one back on again.

Thanks once again!